Online help is important to users of computer-based software such as graphical modeling software. Conventionally, a user-initiated event triggers execution of a software method (a “help callback”) that provides documentation, in displayed or other form, for a graphical object in an application. The properties of the graphical object (appearance, methods, and functionality) depend in general on the domain. The corresponding documentation can vary by domain as well. The domain of a graphical object may be defined by the state of the graphical object, the connections of the graphical object (both the specific graphical objects to which it is connected and the semantics and syntax of the graphical language used) and the state of the native or instantiated digital file containing the graphical object.
In a single-domain environment, all instances of a class of objects have the same appearance and behavior. Consequently, in a single-domain environment, the help system provides the same help for all instances of a class of objects. It typically does this by invoking a callback method that provides the information when the user requests help for an instance of the class.
In a multi-domain environment, the appearance and behavior of instances of a class of objects may vary, depending on the domain in which the objects appear. As a result, the help facility in a multi-domain environment must be able to provide different help for instances of a class of objects, depending on the domain in which the instances occur. It would be desirable for a help system in such a multi-domain environment to be able to determine the domain as well as the type of a graphical object in order to provide domain-sensitive help.